Historically, accusatory testimony by absent witnesses was admissible in some situations, though with the adoption of the the right to have an accuser present at a criminal trial became virtually absolute. Nevertheless, as advances in technology ushered in new kinds of evidence, courts often disagreed about which of these novel categories were subject to the Clause.
The admissibility of scientific evidence has certainly been no exception to this ongoing debate. One issue stemming from this uncertainty — whether scientific evidence in the form of affidavits containing test results is admissible in court absent live testimony??? —
Question now is: Does scienific analysis constitute testimonial evidence???